Cutting die



g- 1942- c. STODDARD ET AL 2,293,036

CUTTING DIE Filed June 4, 1940 I'z'g. 5.

Patented Aug. 18, 1942 CUTTING DIE Charles I. Stoddard, Quincy, and Ernest 0. Larson, Wollaston, Mass.

Application June 4, 1940, Serial No. 338,734

(01. Hi l-29) 6 Claims.

Thisinvention relates to certain improvements in cutting dies, more particularly of the type employed in connection with clicking machines, in cutting out parts of shoe uppers from leather or fabric.

One of the objections to the extensive use of clicking machines has been the cost of the dies, and unless a large number of shoes of the same pattern are to be produced, it has been less expensive to cut out the upper parts with a hand knife from an ordinary pattern than to have a die made.

Various attempts have been made to reduce the cost of producing the dies which are used in connection with clicking machines, and the primary object of the present invention is to reduce the cost of production of these dies.

We accomplish this object by providing a pattern or core which is shaped according to the piece to be .produced, and which is formed from somewhat flexible, fibrous sheet material, providing a two edged blade of annealed steel stock, which is indented at the middle to provide a longitudinal groove on its inner side and a corresponding rib on its outer side, bending the blade about the pattern, so that the edge of the pattern is disposed in the groove of the blade and attaching the ends of the blade, then attaching a similarly indented metal reinforcing strip to the outer side of the blade by spot welding. The pattern is then removed from the groove of the blade by pressure on its surface and then the blade is tempered, after which operation the pattern is preferably restored to its position in the groove of the blade.

For a more complete and detailed disclosure of the invention, reference is now made to the following specification, in connection with the accompanying drawing in which:

Fig. 1 is a perspective view of a cutting die embodying our invention.

Fig. 2 is a sectional View on an enlarged scale at line 22 of Fig. 1.

Figs. 3 and 4 are detail views illustrating the method of initially connecting the ends of the blade.

Fig. 5 is a sectional view illustrating the method of removing the pattern from the blade.

As shown in the drawing a card-board pattern or core I9 is provided of any suitable fibrous sheet material such as is ordinarily employed in making shoe patterns, which are used in connection with a hand knife, and the edge of the pattern is preferably provided with the usual metal binding strip ll.

A two edged blade 12 is provided, which consists of a strip of steel of uniform width, which has preferably been annealed, and a longitudinal groove I3 is indented in the inner side at the,

middle thereof, said groove extending throughout its length and a rib [4 being thereby formed on its outer side.

Said blade is then bent about the pattern so that the edge of the pattern is closely fitted into the groove of the blade at all points, the strip from which the blade is formed being cut at a point which permits the two ends to abut, and the two ends are connected by short metal strips l5 which are spot welded to the inner side of the blade, as shown in Figs. 3 and 4.

A metal reinforcing strip It is provided, which is indented to provide a longitudinal groove ll on its inner side at the middle thereof, forming a rib I8 on its outer side, said groove I1 being adapted to be fitted onto the rib M of the blade, so that the strip will engage the blade at each side of the rib, the width of the strip being less than that of the blade, so that, when in this position, it does not overlap the cutting edge portions of the blade. The reinforcing strip is then placed in said position about the blade and spot welded thereto at each side of the rib I8, as indicated in Figs. 1 and 2, care being taken that the meeting ends of the strip I6 are located at some point other than the point where the ends of the blade meet, as shown in Fig. 1.

The pattern is then removed from the blade by merely pressing it downwardly, as indicated in Fig. 5, the material of which the pattern is made being sufliciently flexible to permit this to be done. The blade is then tempered in the usual manner and the cutting edges sharpened if necessary, and then the pattern is preferably restored to its former position in the blade, as it aids in holding the blade from becoming bent when in use and also provides a convenient means for stamping to indicate sizes etc.

While the above described process is preferable, the blade may be pre-tempered when originally bent about the pattern, so that subsequent tempering is unnecessary, but the annealed blade may be more easily bent about the pattern than the tempered blade and the spot welding operation is more effective on untempered stock than on tempered stock.

With the above described construction, the reinforcing strip so stiffens the blade that it is held securely against lateral bending, so that a blade of the desired width may be employed. The stiffening effect is also increased by spot welding the strip to the blade at opposite sides of the middle thereof.

.We claim: 7

1. A cutting die comprising a blade consisting of a thin metal strip of uniform width having cutting edge portions at both edges and a longitudinal groove indented in the middle thereof at its inner side and providing a corresponding rib at its outer side, a metal reinforcing strip of uniform width having a longitudinal groove indented therein and into which said rib is fitted, the adjacent sides of said reinforcing strip being engaged with the outer sides of said blade and terminating short of the cutting edge portions thereof and a series of spot weld connections being formed between said strip and blade at each side of said rib, said strip and blade being shaped to form a pattern an having their ends connected so that the blade has a continuous cutting edge.

2. A cutting die comprising a blade consisting of a metal strip of uniform width having oppositely disposed cutting edges and a longitudinal groove indented therein midway between said edges and providing a correspondingly disposed rib on the outer side thereof, a metal reinforcing strip of less Width than said bladeand having a longitudinal groove indented in the middle thereof, said rib being fitted into the groove of said reinforcing strip and the portions of said strip and blade at each side of said rib being engaged and spot welded together, and a pattern of flexible sheet material having its edge located in the groove of said blade and said blade being extended about said pattern and having its ends abutting and connected together.

3. A cutting die comprising a blade consisting of a thin metal strip of uniform width having a cutting edge portion and a longitudinal groove indented in one side thereof providing a corresponding rib at its opposite side, a metal reinforcing strip having a longitudinal groove indented therein and into which said rib is fitted, the adjacent sides of said reinforcing strip being engaged with the adjacent sides of the blade and terminating short of the cutting edge portion thereof, and a series of spot weld connections being formed between said strip and blade adjacent said rib, said strip and blade being shaped to form a pattern and having their ends connected so that the blade has a substantially continuous cutting edge.

4. A cutting die comprising a blade consisting of a thin metal strip of uniform width having a cutting edge portion and a longitudinal groove indented in one side thereof, providinga correspondingly disposed rib at the opposite side, a metal reinforcing strip of less width than said blade and having a longitudinal groove indented on one side thereof and forming a corresponding rib at the opposite side, the rib of one strip being fitted into the groove of the other strip and the portions of the strips adjacent the ribs being engaged and spot Welded together, and a pattern of flexible sheet material having its edge fitted in the innermost groove of said strips and said strips extending about the pattern and having their meeting ends connected.

5. A cutting die as in claim 2, wherein the interfitting relation of the pattern and die is such that the pattern is detachable from the die upon fiexure of the pattern.

6. A cutting die as in claim 4, wherein the interfitting relation of the pattern and die is such that the pattern is detachable from the die upon fleXure of the pattern.

CHARLES I. STODDARD. ERNEST O. LARSON. 

